共查询到17条相似文献,搜索用时 125 毫秒
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聚乙炔顺、反式结构对硫化聚乙炔的稳定性及其电子性质的影响 总被引:2,自引:0,他引:2
采用量子化学一维紧束缚的LCAO-SCF-MO法,讨论了顺、反式聚乙炔经硫化得到的硫化聚乙炔的稳定性以及电子性质的变化规律,揭示了顺反结构对其性质影响的原因.计算结果表明,聚乙炔最佳结构为反式,硫化聚乙炔的反式结构更加稳定,这与我们的实验结果一致,为进一步的实验合成提供了理论依据. 相似文献
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采用单元轨道线性组合近似方法对不同端基官能团的聚乙炔体系作了量子化学计算,结果表明卤素对聚乙炔能带结构影响很小,含有氧、氮的官能团(羧基、醛基和硝基)对聚乙炔能带结构有强烈的类似掺杂作用的影响。 相似文献
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以多烯烃模拟聚乙炔链,用CNDO/2方法讨论了各种掺杂剂对聚乙炔性质的影响,掺杂剂使孤子宽度收缩变窄,且p型掺杂剂比n型掺杂剂的影响更大,掺杂剂影响聚乙炔链中的电荷密度波,使电荷主要集中分布于掺杂剂附近的碳原子上。掺杂碱金属时,掺杂剂原子的最高占据轨道与聚乙炔中孤子自旋轨道之间的作用由Li到K依次增强,解释了ESR实验结果。 相似文献
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采用环状原子簇(H3Li)4体系模拟掺杂聚乙炔,进行了abinitio限制性Hartree-Fock自洽场分子轨道计算,得到该体系总能量、能级、键级等数值随形变参数变化的规律,解释了掺杂聚乙炔构型和能带的变化规律、绝缘体金属转变过程及其电导机理等。 相似文献
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D. A. Morton-Blake 《International journal of quantum chemistry》1980,18(4):937-951
In an attempt to apply band-structure calculations to polymers with “reduced” symmetries, and simultaneously to examine some of the causes of band gaps in semiconducting polymers, two types of symmetry reduction are applied on the all-trans polyacetylene chain. Using a neighboring-segment approximation the consequent perturbations were used to calculate changes to the band structure of the undistorted chain and the energy gaps compared with those obtained from a direct calculation on the distorted polymer. 相似文献
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In the present paper, the band structures of valence-band and conduction-band for polyacetylene and Lidoped polyacetylene were calculated by LCAO -SCF ab initio crystal orbital (CO ) method. The influences of doping on the geometric structures, the band structures, and the changes of atomic charges were analyzed and discussed to explain the insulator-conductor transition and electric conducting mechanism of doped polyacetylene. 相似文献
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Yeong‐Soon Gal Sung‐Ho Jin Jong‐Wook Park 《Journal of polymer science. Part A, Polymer chemistry》2007,45(23):5679-5685
A new ionic polyacetylene with two aromatic heterocycles (pyridyl and thienyl) was prepared by the activation polymerization of 2‐ethynylpyridine by using 3‐(6‐bromohexyloxy)methylthiophene without any additional initiator or catalyst. The activated acetylenic triple bond of N‐substituted‐2‐ethynylpyridinium bromide, formed at first quaternarization process, was susceptible to linear polymerization. The instrumental analysis data on the polymer structure revealed that the polymer have the conjugated polyene backbone structure with the designed two aromatic heterocycles. The photoluminescence peak is located at 510 nm corresponding to a photon energy of 2.43eV. The electrochemical properties of this ionic polyacetylene were also measured and discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5679–5685, 2007 相似文献
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A novel functional polyacetylene with D-π-A conjugated quinoline-based heterocyclic azo pendants was designed and prepared to improve the polyacetylene properties. Its structure and properties were characterized and evaluated in details. The incorporation of D-π-A conjugated quinoline-based heterocyclic azo pendants to the polyacetylene backbone increases the polymer solubility in polar solvents. Its UV-vis absorbance is sensitive to the presence of F? anions and results in UV-VIS spectrum red-shift by ca. 21 nm from 449 nm to 470 nm in dry DMSO. 相似文献
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We employ the Laplace-transformed second-order Moller-Plesset perturbation theory for periodic systems in its atomic orbital basis formulation to determine the geometric structure and band gap of interacting polyacetylene chains. We have studied single, double, and triple chains, and also two-dimensional crystals. We estimate from first principles the equilibrium interchain distance and setting angle, along with binding energy between trans-polyacetylene chains due to dispersion interactions. The dependence of the correlation corrected quasiparticle band gap on the intrachain and interchain geometric parameters is studied, obtaining that the gap of the compound structures is substantially reduced with respect to the single chain polymer. 相似文献
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用紧束缚EHT晶体轨道方法对含有过渡金属的聚炔化合物[─C≡C─M(PH_3)_2─C≡C─]_n(M=Pd,Pt,Ni)及[─C≡C─M─C≡C─]_n(M=Cu,Ag,Au)进行了能带结构计算,发现在费米能级附近的导带或价带都是离域的d-pπ键,这些能带对导电性起决定作用。根据重复单元碎片分子轨道和相互作用讨论了能带的组成与碎片分子轨道的相互关系。 相似文献